I do find Ravelry very useful as a Knitter. First and foremost is the availability of inexpensive or free patterns, since the economy has hit me very hard. I do enjoy seeing what is being designed overall, though. When I need yardage for a particular yarn, yarn browsing is very useful. I've taken good advantage of the groups. I find the genealogy the most interesting. Since I can no longer attend a knitting group, it's nice to know that I can find someone on Ravelry to help me with a project if need be.
My favorite statistic from Ravelry is that 4 out of 10 avatars are cats. I've used my cats as avatars